![]() ![]() So reduces overall IR exposure How does filtration affect exposure of the IR As filtration is increased, less photons exit the source thus reducing the number of photons that potentially could strike the IR Does the size of the focal spot being used affect the level of exposure No Do differing generator types affect the level of exposure to the IR Indirectly as some types are more efficient therefore do not require the same amount of mAs to achieve comparable levels of exposure What gives direct feedback of the amount of exposure the film received Density If you needed to see a visible change in density what would you do 30% change in mAs For repeating a density error what would you do Adjust the mAs by a factor of 2 What affects the amount of exposure to the IR kVp Inverse square law formula Process whereby some of the x Ray beam is absorbed in the tissue and some passes through the anatomic part Differential absorption To increase exposure to IR, multiply kVp by 1.15 75 kVp X 1.15 = 86 kVp To decrease exposure to IR multiply kVp by 0.85 75 kVp X 0. ![]() States that changing the kVp by 15% produces the same change in density as does doubling or halving the mAs How does the SID affect exposure of the IR and consequently density Because the x Ray beam diverges in all directions, less photons will strike the IR as the distance between tube and IR increases Inverse square law States that the intensity of the x Ray beam is inversely proportional to the square of the distance from the source What formula would you used to maintain a certain level of density if you were to change the SID The mAs/ distance formula How does changing the OID affect exposure of the IR(and density in analog) Increasing OID will cause more scatter to miss the IR this decreasing overall exposure(and density in analog) How does using a grid affect the exposure of the IR Less photons will strike the IR thus reducing overall exposure How does beam restriction affect exposure of the IR As collimation is increased reducing field size, less patient tissue is exposed decreasing scatter. What percentage of change in mAs is required to see a visual change in density on a radiograph 30% If a change in density is required for a repeat image, how much change should be made Adjust the mAs by a factor of 2 either double or half How does kVp affect exposure and thus density in analog? Digital? Increasing kVp will increase density for both Why should you normally not change density using kVp Because even though you can easily change density by changing the kVp, any change will also change the contrast What is the 15% rule and what does it apply to Applied to density. Brightness can be referred to as the ability to detect differences in Luminance. ![]()
0 Comments
Leave a Reply. |